Telephone-transmitter



(No Model.)

f S. P. NUTT.

. TELEPHONE TRANSMITTER.

Patented June 9, 1885.

s f f l l rect or indirect) of 'the sound-waves.

@NITE STATES TELEPHONE-TRANSMITTER.

SPECIFICATION forming peut of Letters Patent No. 319,927, dated Tune 9, 1885.

Application l'led llebruary 12, 1885. (No model.)

To all whom it may concern:

Beit known that I, S. PnENTIss NUTT, a citizen of the United States, residing at Natchez, in the county of Adams and State of Mississippi, have invented certain new andl useful Improvements in- Telephone Transmitters; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

`This invention has reference to transmitters for. converting sound-waves or sonorous lvibrations into corresponding waves, undulations, or vibrations of electricity by varying the resistance of a circuit traversed by a gal- Vanic current.

It relates more particularly to the current, changer, variable rheostat, or variable resistance, (someti mes called the tension-regulator/U which is acted upon directly or indirectlyby the sound-waves to produce the electrical undulations.

Heretofore this variable rheostat has been composed.commonly, of two or more solid conducting bodies or electrodes held in contact by yielding` pressure. In some cases, however, a liquid of greater or less conductivity has been included in the circuit, so as to constitute a fluid electrode. In instruments having this latter class of rheostats one or more solid electrodes have been moved up and down in the liquid by the action of the diaphragm upon which the sound-waves fall.

The present invention consists, rst, in a new form of variable rheostat. A conducting-liquid constituting a fluid electrode is employed. It is placed in a chamber Whose dimensions are variable under the action (di- A tube communicates with this chamberso that the liquid, according to the pressure exerted on it in said chambcr,will rise and fall in said tube. An opposing electrode makes contact with the liquid in the tube, the rise and fall of which liquid produce vibrations lin the resistance of the rheostat. There are also suitable conductors for including the two electrodes in circuit.

In the instruments using a fluid electrode heretofore devised the movements of the solid l electrodes of course produce by displacement a slight rise and fall of the liquid in the receptacle; but this is essentially different from the rise and fall contemplated by the present improvement. The solid electrode has been so small in comparison with the horizontal area of the liquid that the movement of the latter must be practically inappreciable. Moreover, there has been in -such instruments nothing corresponding to the variable pressure-chamber and tube, the former iilled, the latter partially filled with the conducting-liquid.

In order to diminish the mechanical resistance to the movements of the conductingliquid as much as possible, the tube itself, or a part ofthe tube, is made of conducting material, and constitutes the opposing electrode. This arrangement constitutes a second part of the invention. l

Under the iirst part of the invention it is not essential that the electrode should be or form part of the communicating tube. To the same end the pressure-chamber, instead of being made of variable dimensions by means of a piston or plunger, has one side or wall, or a portion of one side or wall, formed of a thin or flexible plate or membrane,whieh plate or membrane is acted upon (directly or indirectly) by the sound-waves, and presses upon the contained liquid. Such a pressure-chamber, not broadly, but in combination with the tube communicating therewith, the conducting liquid or fluid electrode filling the said chamber andpartially fillingthe said tube, and the opvposing electrode, which may be, and preferably s, the tube itself, or a part of said tube, constitutes thethird part of the invention.

In order to increase the effect of the vibraf tions on the Huid electrode, the tube is made much smaller in cross-section than the area of the movable part of the pressure-chamber, so that the movements of the fluid electrode in said tube are magnified. This arrangement or combination,including the opposing electrode, constitutes the fourth part of the invention.

A telephone-transmitter may be made in.

which the sole variation in resistance is due to the rise and fall of the conducting-liquid in the containing-tube. Such an instrument will IOO with the contained liquid-may, however, be used to vary the pressure between solid electrodes. In this case the column of liquid takes the place of the spring ordinarily used to hold the pressure-electrodes in contact. As the column rises or falls, the pressure upon the electrodes correspondingly increases or diA minishes. This use of a static column is not broadly new. It is, however, believed to be new to make the bore of t-he tube much smaller in cross-section than the area of the movable part ofthe pressure-chamber, rso asto increase the rise and fall in the tube and magnify the variations in pressure due to the rise and fall.

The invent-ion iifthly consists in this combination or arrangement involving two pressure-electrodes, a variable pressure-chamber, a communicating tube whose bore is much smaller than the movable part of the pressurechamber, and a liquid lling-said chainber and partly filling said tube and serving to press the electrodes in contact.

Accordingto the sixth part of the invention, an electrical connection with the electrodes is established through a conducting-liquid in the pressure-chamber and tube.

In some instruments heretofore devised one of the electrodes has been partially depressed in mercury, the pressure of the displaced liquid holding it in contact with an opposing electrode, and the electrical connection has been made through the liquid. In these instruments, however, there was nothing corresponding to the variable pressure-chamber and tube. l

The invention seventhly consists in the coinbinationv of pressure-electrodes with a fluid electrode, its receptacle composed of pressurechamber and tube, and the opposing electrode in contact with said fluid electrode. One of the pressure-electrodes is or may be a part of the pressure-chamber, and the opposing electrode is or may be the communicating tube or a part thereof.

The invention also comprises certain particular constructions, combinations, and arrangements of parts, as hereinafter explained.

Referring to the accompanying drawings, which form a part of this specification, Figure 1 is a central vertical section of a telephone-transmitter constructed in accordance with the invention; Fig. 2, a plan ofthe same; Fig. 3, a partial view in horizontal section;` and Figs. 4 and 5, central vertical sections of other forms of telephone-transmitter, also constructed in accordance with the invention or with parts thereof. Y

In the instrument shown in Figs. l, 2, the diaphragm A is horizontal. i It is made of thin metal, as usual, or preferably of carbon, and is included in the galvanic circuit whose resistance is to be varied. Of course, the diaphragm could be made of other suitableniaterial, as well understood. The diaphragm is or may be supported in any ordinary or suitable way. As shown, it rests at the edges upon an annular shoulder ofthe frame B,and is clamped by the ring D,which is held down by tlie yoke C. One end of the yoke tits in a hole in lug l ofthe frame B, and the other is acted upon by the screw 2, tapped through a lug, 3, and bearing at the end against an incline, 4, on the yoke. The middle of the yoke bears upon the bridge E,attached to or in one piece with the ring D.

The devices which in connection with the diaphragm constitute the current-changer or variable rheostat of the instrument, are adjustably supported in the bridge E. They are as follows: A flexible plate or membrane, F, fastened over the enlarged end of the tube G, constitutes one side of a pressure-chamber, H, with which the tube G communicates. This chamber is filled and the tube G is partly filled with'a conducting-liquid, I-inerciiry, for eX- ample. The plate F, as shown, not only constitutes the flexible wall of the pressurechainber, but also acts as a contact or pressure electrode in connection with the diaphragm A. The plate is or may be made of thin platinum secured by bending the edges over the annular rim 5 and cementing the same to said rim. The center of the plateis dished, so as tohave a suitable bearing against the diaphragm. The tube G, and also the enlargement to form the pressure-chamber, H is or may be of artificial carbon, such as used to make the buttons or pressure-electrodes of ordinary contact-tele-l The tube G, being made of conductphones. ing material, constitutes the opposing electrode for operation in connection with the fluid electrode I. It is, however, properly the upper part, K, `of the tube, including all above a point a little below the lowest point` to which the mercury descends. The rest of the tube nee'd not be conductive, although when the tubeis of a material of low conductivity-such as carbon-it may be.

The tube G ts within the sleeve L,of nonconducting material-hard rubber, for example-and is securedin the bridge E by the setscrew 6,tapped through the meta-l of the bridge, and passing through a hole in the sleeveL and bearing at the end against the outside of the tube G. This set-screw is made of or tipped with non-conducting material, so as to insulate the tube G from the bridge.

The electrode K, making part of the tube G, is provided with a band, 7, whose ends are drawn together by the screw 8. By means of this band the electrode is connected with the circuit-wire. The bore of the tube is much smaller than the area of the flexible wall and pressure-electrode F. It is or may be closed at the upper end by a plug,9. V

The operation will be readily. understood. The tube G is properly adjusted in the bridge E, so that the electrode or flexible plate F bears upon the diaphragm A, whichis also an electrode, with the proper degree of pressure, ascertained by the usual tests. The circuit is through the diaphragm A, the plate or IOO IIO

IZO

lrectly upon the flexible wall F of the pressurechamber H and vary its dimensions, causing the liquid I or fluid electrode to rise and fall in the tube G. In consequence of the relative dimensions of the pressure-chamber and the tube, the liquid has a comparatively large movement in the tube and in contact with the opposing electrode K, formed by the Lupper part of said tube. Vhen the 'liquid rises, the resistance of the instrument is diminished; when it falls, it is increased. The resistance is dilninished by the rise of the liquid, not only in consequence of the increased area of contact between the fluid electrode I and the opposing electrode K and the diminished distance between the top of the mercurycolumn and the circuit-wire, but also because the pressure of the electrode F against the diaphragm is increased as the mercury-column is higher. There is also a variation of resistance due to the variations in pressure between the diaphragm A and the electrode F,

due to the inertia of the liquid, the frictional resistance which it encounters, and the lack of perfect flexibility in plate F. Very good ar ticulation has been obtained with an instrument constructed as described.

Instead of using the precise arrangement described, a button, F, Fig. 4, of' carbon or other suitable material, may be used as the pressure-electrode to rest upon the diaphragm A. It is connected by a'small cylinder, H', of thin sheet-rubber, with the tube G, which is secured in the bridge E, as above described. rI he elasticity of rubber H allows the-button F to rise and fall with the diaphragm, so as to press more or less on the mercury I and cause it to rise and fall in the tube G. The other parts of the instrument are t-he same as in Figs. l. 2, and 3, except that rubber rings 10 are placed on either side of the d iaphragm A at the edges. rI hese rings could of course be used in other instruments, suitable means being used in all cases to connect the diaphragm in circuit. The rubber cylinder H can be fastened to the button F and tube G by wrapping with silk thread.

lIt is not essential to communicate the movements to the duid electrode I, by means of a movable pressure-electrode forming part of' the wall of the pressure-chamber; nor is it necessary to use a solid pressure-electrode at all. An instrument of this kind is shown in Fig. 5. A thin sheet of rubber, F, is stretched across one side of the pressure-chamber H, formed by the enlargement of the tube G, A metal pin, N, attached to the center of the diaphragm, passes through the rubber F and makes Contact with the liquid I.

small disk, 11, fixed on the pin N, 'presses against the rubber membrane F. In this instrument there is no variation in resistance by the variable pressure between solid electrodes. The diaphragm is placed vertically, the tube G being bent so as to make the outer part vertical. rlhe rest of the instrumenti the same as in Figs. l, 2, and 3.

Various other modifications could be made without departing from the spirit of the invention, and parts of the invention could be used separately'.

I claim the new improvements scribed, all and several, to wit:

l. The current-changer or variable rheostat of a telephone-transmitter, comprising avariable pressure-chamber and a conducting liquid or fluid electrode, in combination with an opposing elcctrode and a tube communicating with `said chamber, the souorous vibrations acting through said pressure-chamber to produce arise and fall of the liquid in said tube in contact with the opposing electrode, substantially as described.

2. The combination of a variable pressurechamber, a conducting liquid or iiuid -electrode, a tube communicating with said chamber, and an opposing electrode formed by or forming a part of said tube, substantially as described. y

3. The current-changeror variable resistance of a telephone-transmitter, comprising a conducting liquid or iiuid electrode, a pressure-chamber having a flexible wall, acommunicating tube into which t-he said liquid rises, and an opposing electrode in contact with the liquid in Vthe tube, substantially as described.

4. The current-changer or variable rheost-at of a telephone-transmitter, comprising a conducting liquid or fluid electrode, an opposing electrode in contact with the former, and means for increasing the effect of the souorous vibrations in varying the resistance, said means consisting of' a pressure-chamber. having a relatively large movable part to be actuated by the vibrations and a contracted tube of much smaller bore communicating with said chamber, substantially as described.

5. In a telephone-transmitter, the combination, with two solid or pressure electrodes, of a variable pressure-chamber having a relatively large movable part, a 'tube of much smaller bore communicating with said chamber, and a liquid iilling said chamber and partly filling said tube for pressing the electrodes into contact, the said liquid, under the action of the sound-waves, rising and falling in said tube, and thus varying the pressure upon said electrodes, and the said variations being magnified in consequence of the relatively small bore of the tube, substantially as dcscribed.

6. The combination, with two pressureelectrodes, of a variable pressure-chamber, a communicating tube, a column of conducting-liqhereinv de- IOC IIO

uid filling said chamber and-partly filling said tube for pressing said electrodes into contact, and conductors for establishing an electricall connection with the electrodes through the,

. tluid electrode in said chamber and tube, and

said liquid, substantially as described.

7. The combination, with the two pressure-f electrodes, of the pressurechamber, t-he communicating tube, the conducting-liquid con-v stituting a iluid electrode in said chamber and tube, and the opposing electrode in contact with the liquid in the tube, substantially as described.

8. A telephone-transmitter comprising the following elements in combination, namely:-

a diaphragm, a pressure-chamber Whose dimensions are varied by the vibrations impressed upon the diaphragm, a tube communicating with said chamber, a conducting liq uid or fluid electrode rising in said tube, and an opposing electrode in contact with said liquid in said tube, substantially as described.

9. The current-changer or variable rheostat of atelephone-transmitter,composed of a carbon tube and a column of mercury which isl caused to move in said tube in accordance with the Vibrations to be transmitted, substantiall y as described.

10. The variable pressure-chamber provided with a'tlexible wall, and composed, mainly, ot' carbon, in combination with the carbon tube communicating therewith, and the tiuid elec trode of mercury, substantially as described.

11. Thecurrent-changer or variablerheostat of a telephonetransmitter, comprising a column of conducting-liquid,which constitutes a fluid electrode, and which is made to rise and fall'under the action of the sound-Waves, in combinationwith a stationary opposing electrode.

l2. The combination, with a stationary press- 4o ure-chamber and tube, said pressure-chamber having a tiexible Wall which is acted upon by the sound-waves, of aconductiug liquid or a stationary opposing electrode, substantially as described.

18. The combination ofthe diaphragm held in the stationary frame with .the variable press? ure-chamber and tubevadj ustably supported in the stationary frame, the conducting liquider Huid electrode in said chamberfand tube, and the opposing electrode in'contact with the liquid in the tube, substantially as described.

14. The combination, with the column of conducting-liquid which constitutes th'efluid electrode and is caused to rise and fall under the intiucnee ot' the sound-wavesof an opposing electrode in contact with said column, and a conductor attached to said opposing electrode above 4the top ofsaid column, substantially as described.

l5. The combination of the variable pressnre chamber, the communicating tube, the fluid electrode, the opposing electrode at the upper end of said tnbeand conductors for putting one terminal of the circuit in electrical connection with theliquid inthe pressurechamber and the other terminal in connection with the top of said opposing electrode, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

' s. PRENTiss NUTT.

Witnesses:

PHILIP MAURO, C. J. HEDRIGK. 

